Foundry dump mechanism



B. G. WITTE April 30, 1968 FOUNDRY DUMP MECHANISM 2 Sheets-Sheet 1 Filed Aug. 12, 1966 April 30, 1968 s. G. WITTE 3,380,601

FOUNDRY DUMP MECHANISM Filed Aug. 12, 1966 2 Sheets-Sheet 2 ##MINL-W 1 N VEN TOR. BEE/V4160 6. u/rv'z 3,389,601 FGUNDRY DUMP MECHANISM Bernard G. Witte, Newaygo, Mich, assignor to Newaygo Engineering Company, Newaygo, Mich, a corporation of Michigan Filed Aug. 12, 1966, Ser. No. 572,113 8 Claims. (Ci. 214-4622) This invention relates to mould dump and handling equipment, and more particularly to pneumatically operated and pneumatically controlled mould car dumping and return mechanism.

A variety of mould dump mechanisms have been devised over the last several decades, employing a tiltable track section mounted on a transverse pivot axis intermediate its ends. Such a track section is normally cooperative with an upper track along which the full mould rides on a carrier or car, and cooperable with a lower track along which the empty mould car rides. Due to the economic necessity of automating foundry equipment as much as possible, even in small and medium size foundries, emphasis has been placed on efforts to effect an automatic dumping mechanism that would receive the car from the upper track, tilt it in one direction to dump it, then tilt it in the opposite direction to send the car back along the lower track, and finally tilt back to the initial position to latch to the upper track. One type of mechanism for doing this is illustrated in US. Patent 2,830,716. While automating this series of operations would seem relatively simple, and while the apparatus disclosed in the above identified patent does operate, in every day foundry practice, continued dependable performance of such automated equipment does not always occur due to particular problems occurring in foundries. Particularly, the electrical limit switches, solenoid valve actuators, and signalling devices employed to control the power actuation of the dumping mechanism sooner or later become inoperative or undependable because of dust, sand, and other contaminants penetrating the electrical system.

Consequently, one of the most popular types of mould dumping units today, for small and medium foundries particularly, is that which utilizes the physical weight of the mould and car itself, rather than electrically controlled power units, to cause the various track movements for car dumping, car return, and track relatching. That is, the weight of part of the track plus the loaded mould tips the dumping track in one direction, but the weight of the other part of the track pivots the track and empty car in the opposite direction. However, there is also a significant drawback with units using this weight differential principle, and that is the undependability of the track unit to relatch when it returns into alignment with the receiving track. Because of this factor, a workman must normally be constantly stationed next to the dumping unit to jerk it up into position with a hook so it will be securely latched. Of course, if it does not latch, the next full car will be dumped, load and all, down the return track, to thereby cause great difficulties. Consequently, these prior units, although intended to be automatically operated, normally necessitate an additional workman to assure proper operation.

Another factor which affects this latching action is that each change in the size, weight, or configuration of the mould markedly affects the weight controlled dumping operation and particularly the balance of the unit, so that the present dumping mechanisms must constantly be readjusted to suit each run of particular mould sizes. In actual practice, this prevents the sending of various types of moulds in sequence to the dumping mechanism, since it cannot handle various size moulds without adjustment. Consequently, the foundry operator must regulate his opatent erations to run his mould cars in select groups containing like moulds so that adjustment of the dumper need be made only between groups. This often results in an economic disadvantage.

Another problem common to Weight operated units is the tendency for the full car to drop and dump too violently. Yet, any springs or the like mounted to slow the rapid drop also tends to prevent proper latching of the track mechanism after the car is returned down the return track and the track moves back to the latch position. This is because the spring counteracts the movement of the platform back to the initial latching position.

It is an object of this invention to provide a mould dumping apparatus and system that effectuates a truly automatic dumping operation in a reliable fashion, not

requiring a workman to be present. Extensive test use of the apparatus in actual foundry conditions has proven its complete dependability over an extended period of time.

Another object of this invention is to provide a novel mould dumping mechanism that employs power assist and cushioning mechanism to complement weight differential operation for obtaining effective dumping, yet with controlled cushioned lowering of the full dump car at a rate sufficient to dump it but without the violent lowering action frequently experienced.

Another object of this invention is to provide a novel mould dumping system capable of effectively handling successive moulds of different sizes, types, and weights, yet without readjustment of the mechanism by an operator.

Another object of this invention is to provide a mould dumping mechanism capable of dependable effective dump track latching in alignment with the receiving track after each dump and car return, to thereby assure proper handling of subsequent full mould cars without accidental dumping thereof down the return track, and yet Without requiring any operator to be present.

Another object of this invention is to provide a novel mould dumping action which couples the weight differential action with pneumatical power action, and which is pneumatically controlled, being free of electrical circuitry to become contaminated with dust, sand, and the like.

These and other objects of this invention will become apparent upon studying the following specification in conjunction with the drawings in which:

FIG. 1 is a side elevational view of the novel assembly;

FIG. 2 is a fragmentary plan view of the assembly in FIG. 1;

FIG. 3 is a schematic view of the dumping apparatus and its control system, with the dumping track shown in a latched, car receiving position;

FIG. 4 is a schematic view of the apparatus and system in FIG. 3, shown in an unlatched car dumping position;

FIG. 5 is a schematic view of the apparatus in FIGS. 3 and 4 shown in a reverse tilting movement toward the car return position;

FIG. 6 is a schematic view of the apparatus in FIGS. 3 through 5 shown in the car return position;

FIG. 7 is a schematic view of the appartus being positively returned to the latch position.

Referring now specifically to the drawings, the complete assembly it) includes upper track means l2 for conveying loaded mould cars (not shown) to the dumping platform and track subassembly 14, and lower return track means 16 for receiving empty mould cars from dumping subassembly 14. Upper track means 12 and lower track means 16 may be suitably supported as on a framework composed of interconnected vertical members 18 and 20, diagonal braces 22 and 24, and elongated horizontal beam 30. Such supports undergird and straddle the tracks. Dumping subassembly 14 is pivotally mounted on a transverse pivot shaft 34 supported in bearing sleeves 35 which are mounted to hearing plates 36. These plates are mounted on upwardly extending portion so of longitudinal support beam 30.

Dumping subassembly 1-4 includes a pair of tracks spaced to align with the upper track means 12 and the lower track means 16. Tracks 40 are supported on a platform formed of transverse end members 44 and 46, and elongated connecting members 48 and S0. Pivot shaft 34 is mounted intermediate the ends of the platform, but closer to the downstream free end as shown in FIGS. 1 and 2, so that the greater share of the weight is disposed on the end toward tracks 12 and 16. The downstream end includes a center positioned upright car stop 66. A slanted track 62- leads up to stop 66 on a slight uphill grade. The leading end portion of the dump mechanism has a slightly downhill grade 64. Protruding from stop toward the received car is a shiftable latch actuator 60 having its lower end attached to a shaft 68. The opposite end of shaft 68 includes a latch plate 70 releasably engaged in a slot in latch keeper member 72 aflixed the end of tracks 12. A coil spring 74 around the forward end of shaft 68 is retained between a collar 78 fixed to the framework and a collar 80 mounted on shaft 68. Release of latch plate 70 by longitudinal movement of shaft 68 occurs when a mould car strikes actuator 66 to shift shaft 68 axially and longitudinally, against the compressive resistance of spring '74.

Secured to the end of pivot shaft 34 is a collar 86, having a radially extending arm 88 protruding downwardly therefrom. The arm is pivotally connected at the lower end to a clevis 89 of the extending shaft 90 of a fluid cylinder 92. Cylinder 92 has its opposite end pivotally mounted to the framework. Contraction of cylinder 92 is accompanied by tilting of platform dumping sub assembly 14 in a counterclockwise direction (as viewed in FIG. 1) to a dumping position. Extension of cylinder 92 is accompanied by tilting of platform 14 in a clockwise direction. Counterclockwise movement of this platform is limited by a stop means 106 which abuts member 30 (as shown in phantom lines). Clockwise movement of the platform into alignment with car return track 16 is controlled by stop means 102 that abuts framework 30 (as shown in phantom lines in FIG. 1).

Mounted on a support bracket 104 (FIG. 1), that is secured to beam 36, is a pilot valve 166 of the pneumatic control system. This valve is cam actuated by the radially extending arm 88 in a manner to be described.

The pressurized air to operate cylinder 92 in both directions is supplied through main supply line 114 which branches into lines 114' and 114". Line 114 communicates through a pressure regulator 116 and line 114'a to the rear or blind end of cylinder 92. Line 114%: includes a one-way flow restrictor of a conventional construction capable of restricting flow of air from the blind end of cylinder 92 to exhaust line 118, but allows free flow of air to the cylinder from line 114 and regulator 116. Exhaust line 118 communicates with line 114-a between pressure regulator 116 and cylinder 92. The restrictor 115 regulates the rate of discharge from the blind end of cylinder 92 for reasons to be stated hereinafter. Supply line 114" branches into line 114a to the pilot valve 106, and 114!) which communicates through valve assembly to the opposite front rod end of the cylinder. Valve 120 is a two-position three-way valve enabling straight through communication between lines 1141) and 1140, or between line 1140 and the exhaust line 114d to the atmosphere. Line 114s also has a one-way flow restrictor 115a which is capable of restricting flow of air from the rod end of cylinder 92 to exhaust but allows free flow of air :to the cylinder.

Valve 120 is controlled by pilot valve 166, and pilot valve 106 is controlled by the position of its shiftable cam follower actuator 111 More specifically, shifting of cam follower 119 by leg 83 shifts the two-position threeway pilot valve 106 between an exhaust flow condition from line 114 that communicates between valves 106 and 120, and a second position in which supply line 114a communicates with line 114i to shift two-position threeway valve 120 to its second position.

The pressure regulator 116 is regulated in line 114 to cause a smaller pressure on the blind end of the piston than on the rod end to assure a smaller force tending to tilt platform 14 clockwise than the counteracting force created by a greater pressure on the rod end of the cylinder and tending to tilt platform 14 counterclockwise.

The piston and cylinder are arranged and constructed to cause a definite space between the ends of the cylinder and the piston when it is in its extreme positions, since this has been found to improve the restriction exhaust flow characteristics. This is particularly true with respect to the fully extended position of the piston and rod at the rod end of the cylinder as shown in FIG. 6.

Operation In operation, initially the dumping assembiy assumes the position illustrated in FIG. 3. That is, platform 14 is latched in alignment with the upper tracks, lines 114 and 1140 communicate with the rod end of cylinder 92, and lines 114' and llda communicate with the blind end of the cylinder so that a slight pressure biasing force is applied to the cylinder tending to tilt the latched platform in a counterclockwise direction. When a loaded mould car traverses upper track 16 and moves onto platform 14, when the loaded mould car strikes stop 60 its weight is concentrated on the outer end of means 14, and it simultaneously shifts latch actuator 66 to release latch 70 from keeper 72. The combined weight of the loaded mould car and the free outer end of the platform, plus the slight bias applied by cylinder 92 causes the mould car to pivot platform 14 in a counterclockwise dumping motion. The dropping pivoting action of the platform with the loaded mould car is controlled because the air exhausting from the blind end of cylinder 92 is throttled or restricted as it passes to exhaust line 118. This controls the drop to a reasonable rate.

The movement of the platform to the dumping position is illustrated most clearly in FIG. 4. As platform 14 reaches the dump position, leg 83 shifts pilot valve (as illustrated in FIG. 5), to allow straight through flow from line 114a through line 114 to shift valve 129 to its second position. This connects the rod end of cylinder 92 through line 114 to exhaust line 114d. Since the pressure regulated flow still occurs through lines 114* and 1141: to the opposite blind end of the cylinders, the piston is forced to the left (as viewed in FIG. 5) to tilt the dumping mechanism in a clockwise direction. This movement also is controlled by the throttled exhaust flow. Thus, in spite of the power of cylinder 92, the tilting of the empty mould car to the return position is not violent. AS cylinder 92 reaches the end of its stroke, the dumping platform subassembly 14 is aligned with the return car track 16 as shown in FIG. 6. When the platform reaches the car return position, pilot valve 136 is shifted back to its initial position (as by an internal spring return), to thereby shift control valve 129 back to its initial position allowing airflow from supply line 114 through line 114" through line 11415 through valve 120 to line 1140 and thence to the rod end of the cylinder. Since the pressure applied to the blind end of the piston through lines 114' and 1140, through regulator 116 is smaller than the pressure applied to the rod end of the piston, the piston is forced in the direction to the right (as viewed in FIG. 7) under the resulting pneumatic differential to tilt the platform back in a counterclockwise direction with a definite pneumatic bias. This assures that the platform will move all of the way into the latching position, causing the latch to ride up the tapered camming surface 73 on keeper plate '72 against the momentary bias of spring 74, and into the keeper slot.

Extensive use of the apparatus has proven that the mechanism will always return to a securely latched posi tion, hundreds of times, without an operator being required to achieve this as with prior devices. Yet, the apparatus still utilizes the efiective differential in weight of the mechanism to assist its operation. The apparatus therefore effectively combines weight operated principles with pneumatic power principles, and employs pneumatic controls in a unique manner which eliminates the necessity for electrical controls and assures regulated action and secure latching.

Additional advantages may well occur to those in the art upon studying the foregoing specific preferred form of the inventive system. It is also conceivable that certain minor structural deviations or substitution of components may be made without departing from the concept presented. Hence, the invention is intended to be limited only by the scope of the appended claims and the reasonably equivalent structures to those defined therein.

I claim:

1. Mould car dump mechanism including a dump track section mounted on a transverse pivot axis intermediate its ends for pivoting between a first generally level car receiving position, a second dumping position tilted down toward one end, and a third car return position tilted down toward the second end; said dump track section having car stop means on said one end; releasable latch means for normally retaining said dump track section in said first position and having release actuator means positioned to be operated by a loaded mould car received by said dump track section; fluid cylinder means operably connected to said dump track section; and fluid pressure control means operably associated with said fluid cylinder means, including means to allow weight biased movement of said dump track section with a loaded car thereon from said first position to said second position, to cause movement of said dump track section with an empty car thereon from said second position to said third position, and to apply a pneumatic biasing force on said dump track section by said fluid cylinder means to shift it forceably from said third position back to said first latching position.

2. The mechanism in claim 1 wherein said fluid pressure control means includes throttled exhaust means operably associated with said fluid cylinder means in a manner to apply a pneumatic cushioning action countering said weight biased movement of said dump track section with a loaded car thereon from said first position to said second position.

3. The mechanism in claim 2 wherein said fluid pressure control means includes second throttled exhaust means associated with said fluid cylinder means in a manner to apply a pneumatic cushioning action for said movement from said second position to said third position.

4. The mechanism in claim 1 wherein said fluid pressure control means includes pneumatic pilot valve means operably positioned to be shifted by movement of said dump track section to said third position to apply a pneumatic biasing force by said cylinder means to said dump track section to force it back to said first latching position.

5. The mechanism in claim 1 wherein said fluid pressure control means allows and causes said dump track section to move from said second position to said third position under the influence of (a) Weight diiferential on said dump track section having an empty car thereon and b) a pneumatic assist from said air cylinder means.

6. Mould car dump mechanism including a dump track section mounted on a transverse pivot axis intermediate its ends for pivoting between a first generally level car receiving position, a second dumping position tilted down toward one end, and a third car return position tilted down toward the second end; said dump track section having car stop means on said one end; releasable latch means for normally retaining said dump track section in said first position and having release actuator means positioned to be operated by a loaded mould car received by said dump track section; said dump track section, trans verse pivot axis and car stop means being arranged such that said dump track section will tilt toward said one end when having a loaded mould car thereon, and will tilt toward said second end when having an unloaded mould car thereon; and a pneumatic system including pneumatic power means operably connected to said dump track section and arranged to apply a pneumatic biasing force thereto when said dump track section is tilted down toward said second end, to bias it up into a latched condition at said first car receiving position.

7. The mechanism in claim 6 wherein said pneumatic system includes pneumatic control means adapted to cause said pneumatic power means to apply a force assisting the weight responsive movement of said dump track section from said position to said second position.

8. The mechanism in claim 4 wherein said control means includes a pressure supply conduit to one end of said cylinder means a regulated pressure supply conduit to the second end of said cylinder means to obtain said pneumatic biasing force.

References Cited UNITED STATES PATENTS 2,535,715 12/1950 Anderson 21446.22 2,662,651 12/ 1953 Anderson 214-4622 2,830,716 4/1958 Murphy 21446.22

ROBERT G. SHERIDAN, Primary Examiner. 

1. MOULD CAR DUMP MECHANISM INCLUDING A DUMP TRACK SECTION MOUNTED ON A TRANSVERSE PIVOT AXIS INTERMEDIATE ITS ENDS FOR PIVOTING BETWEEN A FIRST GENERALLY LEVEL CAR RECEIVING POSITION, A SECOND DUMPING POSITION TILTED DOWN TOWARD ONE END, AND A THIRD CAR RETURN POSITION TILTED DOWN TOWARD THE SECOND END; SAID DUMP TRACK SECTION HAVING CAR STOP MEANS ON SAID ONE END; RELEASABLE LATCH MEANS FOR NORMALLY RETAINING SAID DUMP TRACK SECTION IN SAID FIRST POSITION AND HAVING RELEASE ACTUATOR MEANS POSITIONED TO BE OPERATED BY A LOADED MOULD CAR RECEIVED BY SAID DUMP TRACK SECTION; FLUID CYLINDER MEANS OPERABLY CONNECTED TO SAID DUMP TRACK SECTION; AND FLUID PRESSURE CONTROL MEANS OPERABLY ASSOCIATED WITH SAID FLUID CYLINDER MEANS, INCLUDING MEANS TO ALLOW WEIGHT BIASED MOVEMENT OF SAID DUMP TRACK SECTION WITH A LOADED CAR THEREON FROM SAID FIRST POSITION TO SAID SECOND POSITION, TO CAUSE MOVEMENT OF SAID DUMP TRACK SECTION WITH AN EMPTY CAR THEREON FROM SAID SECOND POSITION TO SAID THIRD POSITION, AND TO APPLY A PNEUMATIC BIASING FORCE ON SAID DUMP TRACK SECTION BY SAID FLUID CYLINDER MEANS TO SHIFT IT FORCEABLY FROM SAID THIRD POSITION BACK TO SAID FIRST LATCHING POSITION. 